Use integer division in a certain case.

src/hydrogen-instructions.h

Index: src/hydrogen-instructions.h
===================================================================
--- src/hydrogen-instructions.h	(revision 12214)
+++ src/hydrogen-instructions.h	(working copy)
@@ -557,7 +557,10 @@
     kCanBeDivByZero,
     kDeoptimizeOnUndefined,
     kIsArguments,
+    // This instruction truncates its inputs
     kTruncatingToInt32,
+    // All other instructions will truncate this instruction's output
+    kWillTruncateToInt32,
     kIsDead,
     kLastFlag = kIsDead
   };
@@ -665,6 +668,7 @@
     return use_list_ != NULL && use_list_->tail() != NULL;
   }
   int UseCount() const;
+  int UseCountIgnoringInputsRequiringNone() const;
 
   // Mark this HValue as dead and to be removed from other HValues' use lists.
   void Kill();